The present invention relates to diagnostic testing and more particularly to methods and structures for microorganism identification, wherein a disc-shaped device is provided having a central sample-dispensing chamber communicating with a multiplicity of circumferentially arranged analysis chambers.
Devices useful for the identification of microorganisms or other diagnostic assays requiring a substantially simultaneous multiplicity of determinations, are well-known in the art. Generally the means utilized for bringing samples into contact with substrates (i.e. substances which microbes can utilize or convert to another substance), reagents (i.e. an indicator, something added to a reaction mixture in order to detect the utilization or conversion of a substrate) or inhibitors and the like (or vise versa) fall into four categories: centrifugal force, aspiration/vacuum, positive pressure and gravity. It is common to employ more than one of these means in a single arrangement. The state of the art is exemplified in the following prior art, which individually and collectively demonstrates the previous requirements for complex support equipments and/or manipulations of the sample and/or testing substances.
U.S. Pat. No. 3,776,817 to von der Pfordten discloses a device useful for determining bacterial growth comprising a disc arrangement mounted for rotation, having a central cavity and four equi-spaced apart peripheral cavities. In contrast to the device of the present invention, as example, the peripheral cavities of the von der Pfordten device do not cummunicate with and accordingly are not loaded from the central cavity nor are means provided therefor. The central cavity in this device simultaneously contains both medium and sample, and unlike the present invention is utilized for control for comparative readings with the peripheral cavities.
U.S. Pat. No. 3,759,666 to Hill discloses a disc-shaped rotary device useful for performing a series of analytical determinations on a sample of body fluid. This device contains thirty analytical sites or stations each of which is comprised of a set of three specifically designed and inter-related cavities extending radially inwardly toward a central core area. In operation, one of the inward-most extending cavities for each site is loaded with reagent and the second with sample, only for every other site, thus giving a control for each of fifteen determinations. The reagent and samples, where they are present, are mixed and conveyed by centrifugal force to the outermost cavity for spectrophotometrical reading. Thus, there is, for example, no teaching of filling of the "sample analysis" cavities from a central chamber, by any means, and no teaching of pre-dispensed substances useful in the identification of microorganisms housed in the analysis cavities. Hill is typically representative of the rather large body of patents and published literature covering rotor arrangements in complex and expensive centrifugal analyzers.
U.S. Pat. No. 4,129,419 to Hermann discloses a disposable device for the simultaneous loading of approximately one-third of the receptacles radially arranged around a centrifugal analyzer head. The device comprises a rack holding a number of containers, e.g. test tubes, containing a fluid to be dispensed in equal volumes to compartments in the centrifugal analyzer. In operation, the rack is adjusted to a horizontal orientation and a metered amount of gas under pressure injected into the assembly. The amount of fluid entering each compartment of the analyzer by gravitational flow is thereby controlled by equalization of the pressure within the rack. This assembly inter alia operates on a different principle than the device of the present invention which is concerned for example with simultaneously providing equal quantities of a test sample from a central chamber to peripheral testing chambers.
U.S. Pat. No. 4,154,793 to Guigan discloses a device for conditioning a liquid sample for analysis comprising a disc-like assembly having a central receptacle and peripheral cells connected to the central receptacle by ducts. Each of the cells is characterized by having its inlet for the liquid from the central receptacle proximate its radially outermost surface from the central receptacle and an outlet for escaping air on its radially innermost surface. The disclosed device also differs from the present invention, for example, in that sample from the central receptacle is transferred to the peripheral cavities only through the use of centrifugal force, and the arrangement does not provide for predispensed substances housed in the peripheral cells.
U.S. Pat. No. 3,912,596 to Hague, et. al. discloses a culture disc having radially arranged dividers which extend inwardly from the periphery to define a partially compartmentalized structure with a common central area, which enables the filling of all compartments defined by the dividers simultaneously with a liquid, solidifiable culture medium initially deposited at the central area. By means of a disc having needle-like possessions aligning with wells in a second disc containing sample, the compartments containing solidified medium can be simultaneously innoculated with sample for culture growth. The disclosed assembly is totally different from that of the present invention wherein individual chambers containing different types of media are simultaneously innoculated from a central cavity containing sample.
U.S. Pat. No. 3,912,456 to Young discloses an analytical assembly having a large number of receptacles for receiving specimens and/or reagents from a rotatably mounted aspirator and dispenser arm arrangement. There is, for example, no teaching of a compact disc-shaped device such as the present invention and no teaching of simultaneous innoculation of a multiplicity of peripheral test cavities with sample from a central chamber.
U.S. Pat. No. 3,827,943 to Mann discloses a culture vessel comprising a series of parallel culture tubes having a sealable of inlet/outlet opening at one end and a filter plate opening at the other, said openings being common to all tubes. The tubes are capable of being detached from a support mechanism and being rolled on free or driving wheels or rollers. The device is substantially different from the present invention.
U.S. Pat. No. 3,902,852 to Lemieux, et. al. discloses a mechanism whereby a multiplicity of samples is aspirated from respective sources and delivered to receptacles by a series of syringes. The disclosed mechanism provides for withdrawal of samples from the receptacles in like manner. Although the disclosed device provides for the simultaneous innoculation of a plurality of receptacles with sample via a single mechanical manipulation, the mechanism by which this is achieved is complex and totally different from and fails to respond to several elements of the present invention.
U.S. Pat. No. 3,901,658 to Burtis, et al. discloses a rotor device for separating whole blood and performing diagnostic tests on the plasma thereof. The plasma is provided in measured amounts to diagnostic reagent-containing peripheral chambers from a centrally located bowl. There is, however, neither teaching nor suggestion, for example, as to how the desired separation and analysis might be carried other than through the use of centrifugal force.
U.S. Pat. No. 3,893,891 to Tannenbaum, et al. discloses a diffusion chamber arrangement for growing microorganisms, having a number of organism-populated growth chambers each of which is demountable from a central diffusion reservoir containing a culture medium. The growth chambers are separated from the central reservoir by filters which permit passage of medium and metabolic products but no organisms, thereby retaining the purity of the culture growing within each growth chamber.
U.S. Pat. No. 3,692,488 to Schwartz discloses a device wherein test tubes are mounted in a circular base plate and attached to a central manifold. A flexible container holding reagent is compacted by means of a cam operated by a pump thereby expelling reagent into the manifold and thus into the test tubes. It is stated that the flexible supply container may be compressed by hand if the amount of reagent is relatively small and the exact quantity supplied is not critical. In contrast, the device of the present invention affords a simple and convenient means whereby an exact quantity of sample is uniformly dispensed to each of a series of chambers peripherally arranged about a central dispensing chamber by a single simple hand manipulation and without the need for external means such as a pumping device. The Schwartz arrangement thus fails to respond to several elements of the present invention.
U.S. Pat. No. 3,895,661 to Praglin, et al. discloses a device for determining susceptibility of an organism to a number of antibacteria agents, having a series of compartments arranged in a row which communicate with a common dispensing chamber structure and into which is placed a measured amount of bacterial innoculum and an antibiotic disc. This dispensing structure in turn is disposed to receive the contents of an externally supplied container which is mountable on the device. The contents of the container are emptied into the dispensing chamber by orienting the device via a 1801/4 rotation to allow full-gravity flow. The device is then manipulated to yet another orientation (a 901/4 rotation) to allow gravity flow of the contents of the dispensing chamber into the series of compartments. Antibiotic discs are then separately loaded into the compartments by an elaborate mechanism. Inoculation apparently is carried out with the aid of vacuum conditions. This device, as example, fails to provide simultaneous introduction of a uniform amount of sample into the compartments.
U.S. Pat. No. 4,018,652 to Lanham, et al. discloses a culture medium arrangement for testing a sample of water for bacterial contamination. The disclosed device comprises a cassette having a number of chambers containing culture media with inlet and outlet channels. The inlet channels are connected to a needle-like projection which tightly fits into a tube holding the water specimen to be tested. The wells are filled by means of vacuum which pulls the air from the casette and bubbles it out through the specimen itself. The vacuum it released and the specimen then flows into the wells. There is no suggestion or means other than an externally applied vacuum by which the wells can be with loaded with specimen.
U.S. Pat. No. 3,740,196 to Stroterhoff discloses a device for chemical spot testing for the presence of mustard agents or nerve gas in the air. A device comprises a reaction well containing chemical inhibitors and at least one other compartment or well containing prepackaged reagent solutions, said compartment being connected to the reagent well by a channel. In use, the reaction well is exposed to the atmosphere and one or more agent solutions added thereto by manually rupturing the packages and causing the solutions to flow to the reagent well. This device is likewise clearly distinguishable from the device of the present invention.
With regard to the support films coated with analytical substrates or reagents as disclosed herein in accordance with the present invention, the following prior art is noted.
U.S. Pat. No. 4,148,689 to Hino, et. al. discloses the immobilization of microorganisms having enzymatic activity in a hydrophilic complex gel. The disclosed gel comprises a homogeneous mixture of a water-soluble polymer, such as polyvinyl alcohol, gelatin or a cellulose derivative such as carboxymethylcellulose and a tetraalkoxysilane. The components of a gel are mixed to form a sol, with the desired microbial cells disbursed therein and a resulting mixture gelled under mild conditions. The desired "reagent" is disbursed throughout the resulting gel.
U.S. Pat. No. 3,367,841 to Buissiere, et al. discloses a device for studying living cells comprising in a suitable container a disc having impregnated therein a suitable reagent and color indicator means, the disc being placed on or in juxtaposition with a second larger disc free of the reagents. All of the first disc and a portion of the second disc are covered with a water-and-air-impermeable covering. In use, a specimen to be studied is applied to the exposed portion of the larger disc and, over a period of incubation, mixing of the reagent and sample occurs throughout by capillary action. Results are thereby obtained for both aerobic and non-aerobic conditions.
U.S. Pat. No. 3,416,998 to Streitfeld discloses agar sheets for detecting microorganisms. Each sheet contains disbursed throughout reagents necessary for detecting particular organisms. The sheets, labeled or cut into distinctive shapes are principally intended to be placed on nutrient medium innoculated with test organisms, thereby giving as many individual tests as the number of sheets utilized.
What the prior art particularly lacks is a small, hand-held, inexpensive, versatile and disposable device which possesses inter alia the following combined attributes:
(a) very simple to use; PA1 (b) requires no significant preparation for use beyond the mere introduction of sample; PA1 (c) requires no sterilization or special atmosphere; PA1 (d) has virtually no limitations regarding shelf life and needs no refrigeration; PA1 (e) needs no external equipment (e.g. centrifuges, vaccuum generators or pressure pumps), activating forces or complex manipulations, beyond a single, reversible, very brief, simple hand movement of a self-contained element; and PA1 (f) delivers with this singular movement a uniform amount of sample to each of the multiplicity of analysis locations virtually simultaneously. PA1 (1) lends itself to micro-analytical procedures PA1 (2) adaptable to a wide range of microbiological analyses, biochemical and immunological techniques and to rapid microbial susceptibility testing PA1 (3) adaptable to chemical analysis, such as e.g. measurement of glucose, and enzematic analysis PA1 (4) employable in both manual and automated testing proceedures PA1 (5) readily compatible with programmed analysis for generating interpretive results PA1 (6) provides for greatly reduced reaction times (e.g. 2-4 hrs.)
Beyond these attributes, it is important that such a device be able to provide a large number of analysis locations (for a corresponding large number of tests), notwithstanding availability of only a small amount of sample (starting material), and still meet the uniform distribution requirement for all analysis locations, even if the device is not level when actuated.